Kids from all over town converge to play Vanguard, a card game that seems to be the biggest thing going around. A timid boy, Aichi Sendō, has a rare card, the Blaster Blade, which makes him a target for Katsumi Morikawa, a player who wants to use Aichi's card to get revenge on another player, Toshiki Kai. After school, Morikawa and his buddy Yūta Izaki steal Aichi's Blaster Blade from him. Aichi runs to a card shop called Card Capital to find that Morikawa lost it in a bet against Kai. It is then that Aichi and Kai meet and play a round of Vanguard with Blaster Blade as the prize. Before the match, Kai gives Aichi Blaster Blade in the hopes of him using it effectively against him. During the course of the match, Kai teaches Aichi the rules of playing Vanguard. As the fight goes on, Aichi reveals that he has met Kai before when summoning his ace, Blaster Blade, which Kai gave to him long ago, stating that it was because of him that he wants to learn more about Vanguard.
After Aichi plays Blaster Blade, he and Kai recall their first meeting. Back then, after seeing a young Aichi beaten up, the young Kai cheered him up by giving him Blaster Blade, and he told Aichi to imagine himself as a strong warrior like the card. With that in mind, Aichi got absorbed into Vanguard, creating his own deck in the hopes of playing against Kai, who had already moved away by then. Back to the game, Aichi deals a bit of damage to Kai, who retaliates with his ace card, Dragonic Overlord. It wipes out Aichi's units and greatly damages him. All seems lost until Aichi draws a "Heal Trigger", which allows Aichi to stay in the game for one last turn. Aichi launches a final attack with Blaster Blade, which breaks through Kai's defenses and deals one more point of damage to Kai, thus giving Aichi the win. A day later, Aichi revisits the card shop. Despite thinking that Kai would not show up after being defeated, Aichi is glad to see that Kai returns.
Aichi's little sister, Emi, is worried by Aichi's different behavior as of late. After school, Emi sees Aichi with Morikawa and Izaki, who want him to go with them to the Card Capital. However, Emi misinterprets the situation as Aichi hanging with the wrong crowd. Concerned for her brother, she secretly follows the trio to the Card Capital. There, Emi is astounded by all the people in the shop, icluding Aichi, Morikawa, and Izaki, playing Vanguard. It is then that the card shop's manager, Shin Nitta, appears and introduces Emi to the world of trading card games. Emi and Shin then observe a cardfight between Aichi and Morikawa. The battle ends with Aichi winning without taking any damage. Watching Aichi play, Emi sees how much her big brother has changed because of Vanguard. And so, she has become supportive of Aichi playing the game.
After taking a look at Aichi's deck, Shin decides to show him "something nice". So, Shin has Aichi battle Misaki, who, despite working at the card shop, has never actually participated in a Vanguard fight before. Nonetheless, after Shin gives Misaki a special deck, she and Aichi begin their cardfight. In the midst of the battle, Misaki shows that she knows more about the game than she lets on as she draws multiple cards and calls her ace card, the Grade 3 CEO Amaterasu. Using the "Twin Drive" ability that Grade 3 cards have, Misaki defeats Aichi. Through this loss, Aichi learns that he has much more to know about Vanguard if he ever wants to play against Kai again.
Aichi goes to the card shop to buy a booster pack in the hopes of getting a Grade 3 card. When he arrives, he sees a grade-school kid, Kamui Katsuragi, convincingly defeating Izaki in a cardfight. Aichi challenges Kamui, but he refuses, noticing that Aichi is not a strong player. Then, after Kamui beats Morikawa in a cardfight, Aichi tries to buy a booster pack. Suddenly, Emi appears, and Kamui immediately falls in love with her. Before Aichi could buy a pack, Emi drags him back home while Kamui looks on, thinking that the two are boyfriend and girlfriend. Later, Aichi buys a booster pack and is pleased to find that the pack contained a Grade 3 card, Solitary Knight, Gancelot. Just then, Kamui shows up and challenges Aichi, demanding to get Emi if he beats him. Although Aichi misunderstands Kamui's intentions, he and Kamui begin their Vanguard fight. Kamui uses powerful cards like Genocide Jack and King of Swords to quickly deal a ton of damage to Aichi, who strikes back by using his newly-acquired Solitary Knight, Gancelot. But in the end, Aichi loses to Kamui after he calls his ace card Asura Kaiser. Afterwards, Emi arrives and tries to get Aichi home, and it is then that Kamui learns that the two are actually siblings. Now, hoping to get closer to Emi, Kamui starts referring to Aichi as his "big brother", although Aichi is not exactly glad about it.
Aichi and his friends decide to go to a different card shop called PSY. There, they try out the shop's special Vanguard Fight Stage. It oddly reacts to Aichi, which leads to a woman, Kourin, challenging him to a cardfight. When the two begin the battle, Aichi is surprised that the stage brings the cards to life. Aichi and Kourin, who both use a Royal Paladin deck, continue their battle, until Aichi makes a bad decision in not guarding one of her Vanguard's attacks, ultimately leading to his defeat. Afterwards, another woman, Suiko, gives Aichi the card The King of Knights, Alfred as a special memento for visiting the card shop. Later, Aichi learns from Morikawa that the card shop they visited has disappeared.
Shin introduces the "Standing Fight Table (Name Subject To Change)" to enrich the experience of a Vanguard fight, with Morikawa and Kamui being the first to play on it. After Kamui once again beats Morikawa, Aichi and his friends return to their homes but then see Kai walking back to his home. Wanting to learn where Kai lives, Aichi, Kamui, and Miwa try to follow him, but Kai soon notices them tailing him. Aichi apologizes and tries to get Kai to battle him again, but he declines. However, Kamui challenges Kai, and he reluctantly accepts. The next day, the two commence their cardfight. Kai gains the upper hand by getting a Grade 3 card, Embodiment of Victory, Aleph, into play before Kamui, who counterattacks with his own Grade 3 unit Mr. Invincible. But Kai soon summons another Grade 3 unit Vortex Dragon, and he later activates its Soul Blast skill to destroy some of Kamui's units, leaving Kamui unable to defend himself from Kai's final attacks. Kai defeats Kamui and takes his leave, but not before Aichi tells him that he'll become a stronger and more worthy opponent for him.
The Card Capital Shop Tournament begins soon, but Aichi is hesitant to play in it, even after making a new deck. However, when he learns that Kai will be in the tournament, Aichi decides to enter as well. But when he submits his entry application form, another Vanguard player, Osamu Kishida, places his application at nearly the same time as Aichi. Both of them want to enter, but there is only one open spot left in the tournament. To resolve this issue, Shin recommends to have Aichi and Osamu play against each other to see who gets the last entry spot. Using his Megacolony units' effects, Osamu restricts Aichi's units from standing while scoffing at him for calling so many weak units. However, Aichi uses his new card The King of Knights, Alfred, whose power is increased by the number of other Royal Paladins in play. With Alfred, Aichi defeats Osamu and is therefore officially in the tournament.
The Card Capital Shop Tournament finally begins. In the first round, Aichi must play against Izaki while at the same time, Morikawa battles Misaki. Since this is his first time in a tournament, Aichi grows nervous. His tournament jitters get the better of him as he makes many amateur mistakes. But when he sees that Izaki is also just as nervous and makes similar mistakes, Aichi realizes that he's not alone, regains his composure, and remembers that Vanguard fights should be fun. When he tells Izaki that, he too calms down, and the two continue playing the game at their best. In the end, not only does Aichi win, but Misaki also advances to the next round.
Kamui and Kai advance to the second round of the tournament, along with Ninja Master M, an eccentric player who dresses and acts like a ninja. He meets Aichi, who deduces that he is actually his teacher Mark Whiting, but he denies that claim (even though it's true). The tournament progresses to the second round matches with Aichi facing off against Ninja Master M while Kai plays against the previous tournament's champion Kazuki Inaba. Ninja Master M uses his Nubatama ninja units' effects to deplete the cards in Aichi's hands. He drives Aichi to a corner when he rides his ace card Stealth Dragon Voidmaster and leaves only one card in Aichi's hand. While this is going on, Kai defeats Inaba in his match.
Aichi makes a comeback by calling more units from his deck to boost the power of The King of Knights, Alfred, forcing Ninja Master M to use most of his cards to guard against his attacks. As a result, M is left with no cards to defend himself from Aichi's last attack. Aichi wins and therefore advances to the semifinals. Ninja Master M disappears, and Mark soon arrives (with a bag containing his Ninja Master M attire). After Aichi's match, Kamui and Misaki play in their respective cardfights, and they both advance as well. Before the start of the semifinals, the tournament is put on hold for a lunch break. So, Aichi and Emi have lunch outside the card shop where Kamui tries to get Emi to feed him, but no such luck. After everyone returns to the shop, Aichi, Misaki, Kamui, and Kai all draw lots to determine who will be playing against who. Aichi is put up against Kamui while Kai must fight Misaki. With the matchups set, the semifinals begin.
It's the semifinals: Kai plays against Misaki, and Aichi once again battles Kamui. Both Aichi and Kamui want to win for their own reasons; Aichi wants to fight Kai again while Kamui hopes to gain Emi's affection upon winning the entire tournament. Aichi defends himself from Kamui's Genocide Jack's attacks better than he did in their first cardfight. Aichi makes a surprising move by calling Blaster Blade as a rear-guard and using its ability to destroy Genocide Jack. As the battle between Aichi and Kamui rages on, the cardfight between Kai and Misaki comes to a close with Kai as the victor.
Aichi and Kamui's match comes down to the wire, with Kamui slowly building up his Vanguard's Soul. Despite Aichi getting a Heal Trigger to allow him to stay in the game, Kamui then uses his Mr. Invincible's Soulblast, dubbed the "Tornado Stand Galactica", making all of his units stand up and ready to attack again. With this move, Kamui once again defeats Aichi. After he gets over this loss, the final battle between Kai and Kamui ensues. Even though Kamui uses Mr. Invincible and its Soulblast like in the previous match, Kai nonetheless successfully defends and survives the onslaught. In the end, Kai beats Kamui again and is therefore the champion of the entire tournament. After the tournament, Shin then makes a special announcement: the four finalists (Kai, Kamui, Misaki, and Aichi) of this tournament are to represent Card Capital and participate in the regional tournament, shocking Aichi.
Kamui takes Aichi to Card Shop Handsome, a pirate-themed store that Kamui used to visit. They meet the national-tournament-level and previous regional champions Team Handsome, which is led by Gouki Daimonji. Soon after, they also meet Gouki's little sister Nagisa. She has a huge crush on Kamui to the point that she wants to marry him despite their young age, but he does not feel the same way about her. When Kamui tries to explain that he's in love with Aichi's sister Emi, the situation is misinterpreted as Aichi trying to take away Kamui and hurting Nagisa's feelings. Wanting to make her little sister happy, Gouki challenges Aichi to a Cardfight with the winner getting Kamui. As the fight goes on, Aichi learns the horror of Gouki's Granblue deck as he constantly resurrects his undead pirates from the Drop Zone. The level of a Cardfighter who has played in a national tournament proves to be too much for Aichi; Gouki beats Aichi, learning the level of competition that he will face in the future. After the game, the misunderstanding is cleared, and Nagisa goes back to chasing after Kamui, much to his dismay.
As Emi continues coming to the Card Capital Card Shop, Shin convinces her to try the game out for herself. While approaching the game shop, Katsumi has his fortune told and he finds that he will have luck with his juniors today (however, Yuta corrects him and says that he'll have terrible luck today). When they arrive at the card shop, Aichi is surprised when Emi is preparing to play Vanguard. Emi is handed Misaki's deck as Shin wants both Aichi and Emi to battle together. However, Katsumi wishes to take Aichi's place and a battle between the new player Emi and the "Expert Naive Player" Katsumi begins, with Kamui bitter about how Katsumi is playing against her instead of himself. Despite only using "cute" cards, Emi defeats Katsumi with some beginner's luck.
The day for the regional tournament is here. Shin drives the team of Aichi, Kamui, and Kai to the tournament site. on the way there, while Aichi and Kamui make adjustments to Aichi's deck, Shin decides to name the team "Quadrifoglio" (Italian for "four-leaf-clover"; Q4 for short). They arrive and watch a promotional video of the pop idol group Ultra Rare, who are the three girls, Kourin, Rekka, and Suiko, who Aichi met at the card shop PSY. After a run-in with Team Handsome, it is then accounced that Team Q4 will play in the first round against Team Black Magic, three dark-robed men who all have "Kuro" (Japanese for "black") in their names. Because of Misaki's absence, Aichi will have to participate, and in the first match, too! Aichi's fight does not go well. His opponent, Kurosawa, appears to use the same clan as Kai, the Kagero, but with many new units. When he Superior Rides Demonic Dragon Berserker, Yaksha and uses several skills to retire all of Aichi's Rear-Guards, Aichi panics, realizing that even if he rides Alfred, he cannot use fully use its ability. In a desperate move, he uses all the cards in his hand, including the newly-added Knight of Truth, Gordon, to create an almost full field.
Aichi has difficulty pushing for victory, and his opponent gets a Critical Trigger on top, bringing him to five damage. Aichi desperately needs to block the next strike, but is unwilling to leave his hand empty. He guards with Wingal and Intercepts with his new unit Knight of Truth, Gordon. At first, it seems that Aichi has an insufficient amount of Shield, but he reveals that Gordon's skill, the Especial Intercept, allows its shield to rise by 5000 points during an Intercept. Aichi then proceeds to call Gigantech Charger, another new card whose skill is used to completely fill Aichi's side of the field, and finish the match with a Critical Trigger. Team Black Magic's next fighter, Kurosaki, appears, while on Team Q4's side, Kai steps up. They both use Kagero, and the announcer, MC Miya, and spectators seem to think it will be an exciting match. However, they are soon disillusioned - Kai annihilates his opponent without even breaking a sweat. Afterwards, everyone sees that underneath Team Black Magic's dark cloaks are actually three sparkling-bright young men. Kai's victory leads to Team Q4 advancing to the next round and Kamui becoming enraged that he was not given the chance to fight.
The regional tournament continues with Team Q4 easily plowing through their second and third opponents, Team Martial Arts and Team Chemistry Club, by defeating them both 2-0. Kamui's past relation to Gouki and Team Handsome is revealed, and Gouki and Kamui pledge to be the first to take the stage in the final match. During a break, Emi arrives with lunch, making Kamui happy to eat her food. But this moment is ruined when Nagisa charges in with her own prepared lunch and messes things up for Kamui. Incidentally, both lunches end up in Morikawa's stomach, who spews fire like a dragon from the spicyness of Nagisa's food, which Kamui does not appreciate. After a musical performance by Ultra Rare singing their opening hit song "Miracle Trigger", the tournament finals commence. Kamui, expecting to play against Gouki in the first game, is shocked when Nagisa steps up to be his opponent.
Surprisingly enough, Nagisa steps into the fray as the first fighter of Team Handsome, resulting in Kamui being in a desperate situation as she declares that Kamui has to marry her if she wins. Kamui answers back by declaring that if he wins, then Nagisa will leave him alone. Both parties agree to these terms and then start their Cardfight. Using a Nova Grappler deck like Kamui, Nagisa proves herself to be an excellent fighter, fighting toe-to-toe with him. Though it seems that the agonizing Kamui can make a reversal using Lion Heat, Nagisa is able to fully negate his attacks and finish him off using her own Lion Heat and Magician Girl, Kirara with a "Wedding Hold" during the next turn. After the match, as per agreement, Nagisa gets dressed in a wedding gown and is ready to marry Kamui, who tries to run for his life.
In spite of Nagisa winning and her getting to marry Kamui as a result, Kamui weasels out by saying that Team Q4 as a whole hasn't lost yet, so their agreement is still pending. With one loss in their record, Team Q4 has to win both the next matches in order to advance through the regional tournament. Though everyone is certain that Kai will win, Aichi becomes increasingly desperate, as his match will be the one to decide the fate of the team, going as far as to thinking of running away to have Misaki participate instead. As Kai walks up to play, he indirectly tells Aichi that people who run away are not worthy of fighting him. His opponent, Kaoru "Ka-boom!" Komatsubara, seems to be a formidable opponent who gloats how he's a national-tournament-level player, but Kai gains an early lead, pushing his enemy into a bad situation. Throughout the battle, Kai chooses to not defend against all except one of Kaoru's attacks, puzzling everyone about his decisions. Aichi believes that Kai is trying to tell him something through these actions; he deduces that Kai knows that he does not need to defend and will still be able to win. When both players are at five damage, Kaoru confidently declares that he will survive and claim victory, but Kai refutes that claim, loudly announcing Final Turn! He rides a new card, Blazing Flare Dragon, and uses a card skill to retire one opposing unit and increase its attack power. Kai relentlessly adds to the power by drawing two Critical Triggers in a row, thoroughly annihilating Kaoru. Seeing Kai's power, and remembering his own aspirations to reach his level, Aichi becomes motivated to win his fight!
Aichi's match against Gouki begins. Aichi remembers Gouki as a formidable opponent, and realizes that he cannot stay the same as before if he wishes to win. Using a combination of the skills of Barcgal and Knight of the Future Llew, he Rides Blaster Blade from the deck, surprising Gouki. With both sides getting a Heal Trigger and staying at nearly the same amount of damage, it becomes an intense fight. Gouki Superior Rides Spirit Exceed from the Drop Zone and prepares for a full frontal assault.
The fight between Aichi and Gouki continues. Aichi blocks Gouki's attack, and counterattacks with Alfred, bringing Gouki to five damage. However, Gouki replaces his Vanguard with King of the Demonic Seas, Basskirk, who uses eight cards from the Soul and five cards from the Damage Zone, to instantly revive as many Granblue units from the Drop Zone as possible! Though Aichi perfectly defends during that turn, he realizes that he must finish it immediately. A strange blue light emerges from his deck, which Kai notices. Aichi draws into one of the new cards that he had acquired, which he had put in his deck despite Kamui's advice. He rides Soul Saver Dragon, the powerful God of the Royal Paladin knights, and activates its skill to power up his rear-guard units. Though it seems like Gouki will make it past, Aichi Drive Checks a Stand Trigger, and finishes the game with a brutal attack. With Aichi's win over Gouki, Team Q4 wins the regional tournament and is therefore eligible to enter the national tournament. At the awards ceremony, Ultra Rare congratulates Q4 for their victory, and Suiko invites Aichi to visit PSY once more.
Aichi, Kamui and Misaki visit Card Shop PSY after Suiko's invitation. They meet an aloof red-haired stranger with a peculiar attitude. However, once the Ultra Rare group arrives, they learn that he is none other than Ren Suzugamori, the winner of the previous national tournament! Kourin and Ren engage in a Cardfight, both using the exact same deck structure, and Aichi, who had been beaten by Kourin before, watches in amazement as Ren easily controls the match. Strangely using the same speech patterns that Kai does during his matches, Ren uses a seemingly simple Grade 1 card called Blazer Idols to finish the game. However, what are these visions that Aichi has of the planet Cray, when Ren is about to make his move...?
To prepare for the national tournaments, worried about Cardfighters on Ren's level, Aichi and Misaki engage in a fight. However, memories of her tragic past surface in Misaki's mind, causing her to break down. Though she dominates the match by preventing Aichi's strategy from taking effect until it is too late, and finishing him off by means of a Critical Trigger, she abandons the team directly afterwards, claiming to be unable to fight any longer. Stunned, Aichi and Kamui try to discover what they have done wrong...
Emi visits Card Capital, worrying about the depressed Aichi. She encounters Misaki, who claims not to know anything - but the manager pushes the two into a cardfight using the new trial decks that just arrived. Going along for Emi's sake, Misaki uses the new Nova Grappler deck, whereas Emi uses the Oracle Think Tank one. Already having memorized all effects of the cards with her perfect memory, Misaki easily defeats Emi, but in doing so, she remembers the fun that Vanguard used to be for both her and her parents, and realizes that they would not want her to feel sad about the game. Receiving a key from her uncle to unlock the box with the deck her parents made for her, she rejoins Team Q4 to Aichi and Kamui's joy, who feel terrible about what had happened, and easily beats every regular customer of the shop.
Team Q4 arrives at the site of the national tournament grounds and meets Team Caesar, composed of Kenji "Koutei" Matsusada and the siblings Gai and Yuri Usui, who were the last national tournament's finalists and previous winners. Everything seems to be going well, but due to Kai's increasingly arrogant and insulting attitude, Kamui decides he can no longer work with him and abandons the team. Aichi attempts to go after him, but is reminded that if he also leaves, Team Q4 will be unable to participate in the tournament and will therefore be disqualified. With some advice from Kenji, Aichi decides to win the preliminary rounds and earn Q4 a spot in the finals, so Kamui can return.
The national tournament preliminary rounds begin! After an explanation of the tournament rules by Ultra Rare, Team Q4 discovers that they are put in the same block as Team Foo Fighter Apex Limited Four, Ren Suzugamori's team and previous winners. To his great surprise, Aichi discovers that Kai not only personally knows one of AL4's members, but is also acquainted with Ren. They are soon forced to forget about AL4, though, since the first round begins and pits them against Team Jurassic Army, a group of militaristic Cardfighters using the brutal Tachikaze clan. Aichi takes the first match against Gunji, and though he allows himself to take damage and use the skill of Blaster Blade effectively, he is cornered by the Tachikaze ace, Tyrant, Deathrex...
Gunji brutally corners Aichi with the speed and power of his Tachikaze deck, bringing the score to 5-3 in Gunji's favor. To make a reversal, Aichi rides his new ace card, Soul Saver Dragon. Managing to get a Critical trigger, it looks like the match has been decided, but luck favors Gunji, who gets a last-minute Heal Trigger and survives, winning on the next turn. The next match features Misaki who, despite cleverly using the attribute of Silent Tom to cripple her opponent's ability to guard, is also defeated in the exact same manner. With their first match ending in a brutal defeat, Team Q4 cannot afford to lose again.
Team Q4's second match against Team Muscle Brain begins. Team Muscle Brain believes that training the body will result in a better mind, and thus practices brutal fighting prowess. However, when Kai steps up to the first match, he is able to annihilate his opponent easily by Superior Riding Blazing Flare Dragon. Misaki takes the second match, using a new line of cards located in the deck that was given to her by her parents before their death. Though she can't seem to get a Grade 3 in hand, using the effects of her units she Superior Rides Goddess of the Full Moon Tsukuyomi. Using skills that allow her to draw, she increases her hand to the point where she comfortably blocks her opponent's desperate move, and finishes the game. There is no time to celebrate, though, as the next match is versus Team AL4, the strongest team.
Team Q4's final fight in the preliminary rounds, which they cannot afford to lose, begins. Kai takes the stage first, against AL4 member "Crusher" Kyou Yahagi, who potently uses a Spike Brothers deck. Kai rides Dragonic Overlord and activates its skill, but Kyou blocks it, pushing Kai on the defensive. However, Kai recovers his momentum with a Heal Trigger, allowing him to reclaim three unflipped damage. He uses Overlord's effect once more, annihilating Kyou's defense and claiming victory. An observing Ren claims the result was not unexpected and grins madly, while Kyou runs off in panic.
Though Kai won the first match of the team battle, Misaki is challenged by Asaka Narumi, known as the "Assassin". Asaka skillfully uses a Pale Moon deck, and though Misaki tries to fight by reading her opponent's moves, Asaka plans further ahead and cripples Misaki's strategy while preparing her field. Using an unavoidable three-pronged attack pattern coupled with a Draw Trigger, Asaka delivers the final blow to Misaki. This leaves both teams with a single match won, and it is up to Aichi to determine Q4's fate against Tetsu, the General of AL4. Tetsu, using a Dark Irregulars deck, deals 3 damage to Aichi in his very first turn - however, Aichi has a plan.
The match between Aichi and Tetsu continues while an anxious Kamui watches. Confronted by Nagisa, Gouki and Emi, who learned of the situation via Team Caesar, Kamui is motivated to support Aichi. Aichi begins to make a comeback by shutting down his opponent's offense and evening out the damage with a heal trigger, but Tetsu rides Demon World Marquis Amon, and with a Critical Trigger, pushes Aichi down to five damage. Aichi gains a vision of the Royal Paladin knights joined together, and draws and rides Soul Saver Dragon, whose effect is used to power up all his units. Regardless, Tetsu manages to block, and during his next turn rides Still Vampyr. That card has a deadly effect that replaces the opponent's Vanguard with another Rear-Guard, thus Aichi is forced to ride the Grade 0 Future Knight, Llew. In this weakened form, he is unable to withstand Tetsu's attack and suffers a terrible defeat. It seems as if all hope is not lost, as Jurassic Army loses to Muscle Brain and a 3-way tie is formed. Through a final judges' call based on overall performance, Ultra Rare announces that Jurassic Army is the team that progress. Ren meets up with Q4 and tries to get Kai to rejoin his team, but Kai refuses him, and Ren blames Aichi for Q4's failure.
Team Q4 gathers at Card Capital to watch the national tournament finals. Due to various delays, they only manage to catch the very last match, where Ren, leader of Foo Fighter AL4, faces of against Kenji, leader of Team Caesar. Even though Kenji appears to put up a good fight, Aichi sees right through Ren's power. Ren quickly decides to take the battle a little more seriously, and rides Blaster Dark, a black version of Blaster Blade. In a couple of turns, he completely annihilates Kenji, and AL4 are crowned the national champions. In an attempt to cheer Q4 up, Shin arranges for a beach trip, but Aichi is too demotivated for it. Miwa manages to convince Kai to speak to Aichi. Kai's words give Aichi the motivation to continue playing. Fired up, Q4 requests a special training session from Shin.
Q4 has gone to the beach in order to train at Vanguard - though a lot of its supporters, such as Katsumi, seem to have other priorities. The team meets up with Team Caesar, who set up the training camp, and they quickly engage in cardfights. Surprising everyone, Kai actually defeats Kenji, and the two engage in an elaborate discussion about strategies and tactics. In the meantime, Aichi loses to Yuri five times in a row. Yuri requests to see Aichi's deck, and once she does acknowledges that it's a good deck, but with a weak unifying victory strategy. Aichi thinks about her words as everyone prepares curry for dinner, and while everyone else sleeps, he begins working on his deck.
Aichi sleeps late and is thus the last to get up. Kai and Kenji have woken up before everyone else and are already engaged in Cardfighting. They have leftover curry for breakfast, while Aichi reports the unfortunate results of his deck editing session. They go to the beach, where Aichi, Katsumi and Yūta are put under a special training regimine by Kamui, which culminates in them imagining themselves as valiant Vanguards on Cray. Shin presents Q4 with a briefcase full of rare cards, which they used to build up their decks. Aichi's Royal Paladins speak to him in his mind, and he reconstructs his deck without realizing it. Yuri challenges Aichi to a rematch, and Aichi skillfully uses the effects of Hi-Dog Breeder Akane and Pongal to get Soul Saver Dragon in his hand, before Katsumi interrupts the match. The team finally leaves the training camp, satisfied with the experience they have gathered.
Miwa spys on Kai who has begun fighting in underground fights in order to find stronger opponents. Underground Cardfights usually result in the loss of cards, and players do not abide by the rules that ensure fair play in a Cardfight. When Miwa discovers that Kai is searching for Jun, the King of Underground Fights, he goes looking for him. He confronts Jun, and is captured. Jun and Kai then have a Cardfight with Miwa and Kai's freedom at stake. Jun uses a Dark Irregulars deck against Kai, and puts up a fierce fight by making use of his cards' abilities. At the end, he attempts to use his ace, Edel Rose, and her critical strike ability to finish off Kai, but is prevented by the complete defense of Kai's Wyvern Guard, Barri. Kai and Miwa leave, with Miwa figuring out that he had been used by Kai to draw Jun out.
A tournament is being held again at Card Capital, but it is now a team fight due to the large number of participants. Team Q4 fights and moves all the way up to the final round, with Kai not participating in the team fight. Q4 discovers their opponent to be Team Overthrow which consists of Miwa, Yūta, and Katsumi, who is dressed up as Ninja Master M, since the costume was donated to him by M, since he decided to not participate in tournaments anymore. In the first round, Katsumi faces Misaki and completely loses due to his deck being full of grade 3s. The second round features Kamui and Degozaru's secret weapon, Princess Maiden, who is actually Emi, who wanted to participate in the tournament. Because of Kamui being unwilling to give his all against Emi, she defeats him using her Bermuda Triangle/Oracle Think Tank deck. Now it is Aichi's turn, and his opponent is none other than Miwa!
The fight between Miwa and Aichi begins. Miwa, who surprisingly uses a Kagero deck like Kai, forces Aichi into a corner by using powerful retiring strategies, and even though Aichi manages a powerful attack using two Pongal and Young Pegasus Knight, and then Solitary Knight, Gancelot as well as Soul Saver Dragon, Miwa blocks his efforts, and calls Dragonic Overlord, activating its Eternal Flame. Though Miwa gloats with 'Final Turn', Aichi blocks his attack, and then places down Flash Shield, Iseult to neutralize Overlord's hit. He proceeds to win the game using Soul Saver Dragon - however, Kai is informed by Miwa that Aichi hears the call of card spirits, which greatly worries him.
The regionals commence once again, with Team Q4 and Team Handsome competing. Battles rage as Team Handsome advances to the next round. Team Q4's first opponent, though, is Team Fragrance, a dangerous group whose members claim to be able to sense their opponent's feelings by their scent. Aichi displays extraordinary positiveness by claiming the first spot for Q4, and proceeds to the fighting arena.
Aichi trusts the voice of his cards, riding Solitary Knight, Gancelot and calling King of Knights, Alfred to the Rear-Guard circle. His opponent uses an Oracle Think Tank deck. Though his first Counter Blast with Gancelot is thwarted by Chocolat, he tries again during the next turn, and scores an unexpected Critical trigger, winning the match. Misaki proceeds to win the second fight with a clever combination of Oracle Guardian Red-Eye and Goddess of the Full Moon Tsukuyomi. Team Q4 also advances, but Aichi seems exhausted from his previous fight and collapses, unable to continue. The next fights are conducted without his presence, and Kamui and Kai easily dominate their opponents, allowing Q4 to move once more to the very last round, where they hope to face Team Handsome. However, Gouki and the others are defeated by a mysterious team called Avengers, whose leader is revealed to be none other than "Crusher" Kyou Yahagi, seeking revenge against Kai...
Kyou is back for revenge against Team Q4 - specifically Kai. Kyou then proceeds to explain how things came to be this way - since he lost his match to Kai during the Nationals, he got banished from AL4. As a former member of AL4, Kyou had trouble finding a new team to join because no one wants to recruit a discarded AL4 member to prevent any conflicts. After multiple rejections, Kyou goes insane and swears vengeance against Team Q4. For the first match, Aichi decides to take the lead instead of letting Kai face Kyou again in hopes of earning more of Kai's acknowledgement. Under the influence of his new powers, Aichi becomes a completely different Cardfighter. Before the match, Aichi declares his victory and the card Young Pegasus Knight as the key card to win the match - something that Ren would do. During the match, Kyou slowly becomes intimidated by Aichi's resemblance to Ren. Kyou believed Aichi was simply bluffing after retiring his Young Pegasus Knight during his second turn. But at the end, Aichi reveals the second Young Pegasus Knight he had and declared his victory with the same attitude and aura as Ren.
After easily blocking Kyou's quadruple attack, Aichi declares 'Final Turn'. Though it seems his plan is going to be defeated, thanks to a Stand trigger, Aichi manages to deliver the finishing blow using Young Pegasus Knight. It is determined by Suiko that Aichi possesses the ability PSY Qualia, which they seek. Kyou has a vision of planet Cray, where he is slashed down by Pegasus Knight, and collapses, obliterated. Similarly, an exhausted Aichi falls in Kai's arms, and he is brought to the infirmary. The second match between Misaki and Team Avenger's second member begins. Aichi is visited by Emi, who claims Aichi looked scary during his fight, though Aichi doesn't notice anything different. Misaki wins her fight, though Suiko and the others decide she doesn't possess the ability PSY Qualia. Aichi is visited by Kai, and although he seeks his approval for becoming stronger, Kai calls him weak, and abandons him and Team Q4 after Aichi challenges him to a fight in order to prove his strength. Kyou continues seeking his revenge, until Team Brilliant Stars appears, ordering Kyou and the others to be arrested.
Kamui is concerned when Aichi stops coming to Card Capital after the tournament. Aichi continues to be haunted by Kai's words and finds himself unexpectedly at the door to the PSY Card Shop. Aichi enters the shop and is greeted by the members of Ultra Rare where he asks them if he was strong in the last tournament. Everyone is then surprised when Ren enters the shop. Confronting Aichi, Ren explains what has been happening to him lately and the nature of the power, PSY Qualia. Ren tells Aichi that Kai will only acknowledge strong fighters and that he must get stronger. Ren then gives Aichi a Shadow Paladin Deck, the dark opposite of his Royal Paladin Deck. Seeing through PSY Qualia, Aichi is nearly overwhelmed by the deck's power and believes this new deck makes him invincible. Kourin believes he's being arrogant and challenges him to a duel with her Royal Paladin Deck. In the match, Kourin is easily and soundly defeated by Aichi using Blaster Dark and his new Shadow Paladins, demonstrating the fearsome power of PSY Qualia. All the while, Ren watches from the shadows, smiling and encouraging Aichi to embrace his new dark power.
After losing to Aichi, Kourin goes to Card Capital, asking for Kai. Since Miwa is the only person who knows where Kai is, he rides with Kourin to the Underground cardfight area. They find Kai, who is beating all the underground fighters to relieve his frustrations. Kourin soon challenges him to a fight, where Miwa and Jun get to sit in the middle of the action. While Kourin uses her Royal Paladin deck, Kai reveals his newly modified Kagero deck, which focuses on Amber Dragons. As each of them are dealing damage to each other, Kourin confronts Kai about how it's his fault that Aichi has fallen into the power of Psy Qualia, saying that Aichi only sought the power because he wanted to become stronger for Kai's approval. Kai agrees, and also claims that he had seen the corrupted effects of Psy Qualia before, not knowing how to prevent it from happening. He then tells Kourin that it may have been one simple thing: to exceed that power. Kourin then asks Kai if he can stop Aichi before he falls completely under the influence of Psy Qualia, to which Kai says that he can. After losing to Kai, Kourin gives him Aichi's Royal Paladin deck, and hopes that he can succeed where she had failed. Meanwhile, Aichi spends the entire night in his room, mentally preparing himself for the National Tournament. When arriving at the tournament, Aichi tells Kamui to relax as he is sure that they will win, revealing his newly acquired Shadow Paladin deck, much to the shock of his teammates.
At the start of the tournament, Team Q4 is placed in the same block as Team Jurassic Army and Team Brilliant Stars, another faction of Foo Fighters. After having a brief conversation with Team Q4, Kiriya Bidou, leader of Brilliant Stars, is summoned by Ren, who tells him that if he can take care of Aichi, then he will be allowed into AL4. When Team Q4 is getting ready to face Jurassic Army, they are greeted by the members of Team Caesar, who wish them luck to meet in the finals. Aichi then claims that even without luck, they will be at the finals, since their victory is guaranteed, puzzling Team Caesar. As he steps onto the field, Aichi is once again faced off against Gunji, who asks if he has gotten stronger since their last match. Fed up with people asking how much stronger he has gotten, Aichi tells Gunji that it is best to just show much power he has, and warns him that he will soundly defeat him. Using his new Shadow Paladin deck, Aichi beats Gunji, despite drawing a heal trigger like last time. Although Gunji claims that Aichi has gotten stronger, it is not something that should be praised for. Soonafter, Ren claims that Aichi still has not released his true powers, as Aichi once again collapses from using Psy Qualia. As Aichi is resting in the infirmary, both Kamui and Misaki agree that till the finals, they would not let Aichi fight again, while Kourin returns, hoping that Kai will make it in time to help Aichi.
After defeating Jurassic Army, Team Q4 are now up against Team Spyder, and Kamui easily defeats his opponent using Stern Blaukruger, despite being tricked throughout his match. Misaki is up next, but her opponent uses data to attack and uses the skills of deadly cards like Elite Mutant, Giraffa and Ant Lion to choose units from Misaki's field to not stand next turn. Even with that, she drew Goddess of the Full Moon, Tsukuyomi and uses counterblast to replace all her rear-guard units. With that, they move on to face their last opponents in the C Block, FFBS (Foo Fighter Brilliant Stars).
Team Q4 proceed to fight Team FFBS and Kamui is up first, facing Hiromi from FFBS. Hiromi then used the skills of Young Pegasus Knight, Hi-Dog Breeder Akane, Great Sage Barron, Knight of God-speed Galahad and Margal to power up her units. Kamui skillfully defends and used the skill of Stern Blaukruger to stand Stern and the unit behind him to finish the fight. Hiromi congratulates Kamui about winning the first fight, but tells him that their victory as a team had vanished. Aichi then wakes up and manages to watch Misaki's fight, and found out that Misaki had lost the match due to Sealed Dragon Blockade, a vicious card that disables Misaki's rear-guards to intercept. After watching the fight, Aichi slowly makes his way to the fighting area to start the third fight. As he walks towards the Motion Figure System, Shin, Misaki and Kamui were shocked. Aichi tells Misaki and Kamui that he was disappointed in the two and gave them and confident, evil smile. His opponent, Kiriya Bidou told Aichi he was convinced that Aichi would run away and Aichi replied, saying that there was no need to be afraid of him. The fight begins!!
As the fight between Kiriya and Aichi begins, Kai is seen watching the match in another area. Emi runs to Team Q4, worried about Aichi playing in another fight, but finds both Misaki and Kamui visibly shaken from Aichi's words. While the fan girls for Brilliant Stars are cheering, Kiriya is still wondering if Aichi has really mastered the Shadow Paladin Deck, while deciding to prove his worth by beating him in front of Ren. With his Pale Moon Deck, Kiriya successfully deals damage to Aichi with his Juggler cards and calling cards from the Soul. Aichi simply takes a few damage and defends himself with a couple of cards, all while taunting Kiriya about Ren giving him the Shadow Paladin Deck because he is strong. After riding Dark Illusionist, Robert, Kiriya is able to deal three damage to Aichi, giving him almost complete control of the match. However, as Miwa states, Aichi is just playing around with Kiriya, as he rides Phantom Blaster Dragon, and calls Blaster Dark to the rear guard to help deal damage. Kiriya is able to defend himself, allowing only one damage as he eagerly calls "Final Turn" on Aichi. With Ren watching, Kiriya stands in shock as Aichi completely defends himself and takes no damage. Wondering if Kai is watching his fight, Aichi claims he will show how strong he is, calling his "Final Turn" on Kiriya. Calling two more Grade 3 units, Aichi soundly defeats Kiriya, while still muttering that he needs to be even stronger for Kai's recognition. As everyone in the stadium cheers Team Q4 for winning the elimination rounds, Ren congratulates Aichi for winning, while forgetting who Kiriya is. Meanwhile, Kai is seen walking away from watching the match, swearing to himself that he will stop Aichi.
Kai heads to the Underground area to await his fateful match with Aichi. Back at home, as Aichi reviews his Shadow Paladin deck, he receives a Psy Qualia induced summon from Ren who is waiting for him at Card Shop PSY. Aichi, led by Ren's Psy Qualia summon reaches as far as outside the Card Shop when Kourin suddenly rides up throws him a helmet & tells him to come with her. Back at the Underground area, Miwa shows up with Misaki & Kamui who both implore Kai to face Aichi in a Vanguard fight and help bring him back to normal. Just as Kai informs them that that is exactly why he is here, Kourin immediately arrives with Aichi. Miwa, Kourin, Misaki & Kamui clear the area to watch the fight from a distance. Kai upsets Aichi when tells him that he still thinks he is weak & Aichi vows to prove his strength to Kai as they get ready to begin their fierce battle. Aichi is startled when he realizes Kai is going to fight him with his former Royal Paladin deck. Kai vows to show Aichi the "true power" of the deck that he threw away which rattles Aichi even more. Aichi goes first & uses his units' skills to add Blaster Dark who he refers to as his avatar from his deck to his hand. Kai has a flashback of losing his parents 4 years ago & meeting Ren from his new school & later Tetsu (after he leaves town to live with his uncle). Tetsu loses to Kai in a Cardfight & he and Ren tell Kai of Foo Fighter. They recruit Kai & they have a love of fun until one day Ren's Psy Qualia powers awakened. He beat Tetsu repeatedly claiming that he was now the "strongest fighter" ever. Ren abandoned the idea of him, Tetsu & Kai being Team Foo Fighter & has construction begin for the new Foo Fighters Headquarters where only the best fighters would be selected. Kai realizes that Ren has become obsessed with power and refuses to go along with his new plan & quickly challenges him to a card fight. The match is fierce and as Ren announces his "Final Turn" he taunts Kai but before he can claim victory his overuse of his PSY Qualia power causes him to collapse. Kai catches him in time but Ren is still fixated on how much stronger he's become. Kai quits the team & moves back home peeved about how powerless he was to stop Ren. He reminisces on how refreshing after all of this it was to meet Aichi again and of how much fun Aichi made him remember Vanguard fights to be. He also remembers how fixated Aichi had become on "getting stronger". He vows to himself that while he couldn't stop Ren, this time will be different. With stern determination to accomplish this, Kai draws & uses his units' skills to add Blaster Blade from his deck to his hand. Kai reminds Aichi that then & now his avatar is not Blaster Dark as he claims but will always be Blaster Blade. Kai faces Aichi thinking that this time he's going to teach him what true strength is & declares that he is going to stop him!
Kai rides King of Knights, Alfred to give Aichi some damage. However, on the next turn, Aichi declares "Final Turn", attacking with Phantom Blaster Dragon and Blaster Dark attacks but Kai successfully guards against both of them. Failing his Final Turn, Aichi is shocked and forced to end his turn, giving Kai the chance to show Aichi what true strength is. Kai declares "Final Turn" as he rides Alfred Early, a more powerful form of King of Knights, Alfred. Through Alfred Early's skill, Blaster Blade is Superior Called from the soul. Blaster Blade makes Aichi realize that relying on PSY Qualia isn't real power and how Aichi always wanted to have a Cardfight with Kai. The fight is called off, and Kai gives back Aichi's Royal Paladin deck.
Card Capital is holding a casual shop tournament, and Aichi, Kamui, and Morikawa enter in the senior division, while Emi competes in the junior division. Unfortunately, Morikawa has left his super-strong deck at home. Shin lends Morikawa an unmodified trial deck to use, but to his dismay it contains only one Grade 3. Can Golden Rutile go the distance?
The shop tournament continues, with Morikawa having a seemingly unstoppable series of victories and Emi's Bermuda Triangle deck dominating the junior division. Though he doesn't win, Aichi realizes that he plays Vanguard because it's fun.
The tournament finals begin and Ren delivers an egotistical speech at the beginning that angers the other teams. Team Q4 battles through the first two rounds, but coming up next is their "rivals", Team Caesar.
In the first battle of the semi-finals, Kamui faces off against Gai Usui, the "Gladiator" of Team Caesar.
The second match is between Misaki and Yuri, two female fighters with completely different playstyles. While Misaki makes her decisions based on highest probabilities and most logical outcomes, Yuri relies on her intuition to take high risks for greater rewards. The latter strategy holds true as Misaki makes a grave misplay by not going for said high risks which could have won her the match. Showing the reason why she is called the Empress, Yuri uses her instincts to draw a Stand Trigger as if she commanded her deck to allow her to do so, thus giving her enough power to defeat Misaki and take the second game. With the score tied 1-1, the last match between Kenji and Aichi will decide who will go on to the finals. As both players deal damage to each other, Aichi sets up to play Soul Saver Dragon in his next turn. However, Kenji sees through Aichi's plan and intends to put a dent in it.
Aichi battles Kenji the Emperor for the right to face Team AL4 in the finals. Can Aichi defeat his strongest opponent yet without relying on his PSY Qualia?
Although happy that Aichi woke up, Kai thought of the time when he was still young. He wanted to get Ren out of his Pysqualia self, but then Ren's image was so bad that Kai left him defeated. Now that Kai changed, he vowed to rescue Ren from his PSY Qualia addiction and is bent on winning!
Determined to turn Ren back to his former self, Kai crossrides Dragonic Overlord The End and performed Persona Blast to get Ren out of his PSY Qualia self. It didn't get Ren out of the box but got him to also crossride his own trump card (which is given by Suiko)Phantom Blaster Overlord. The period was to prepare for the worse as Phantom Blaster Overlord had the same ability as The End and could also do Persona Blast which destroyed The End. Because of this failed battle, it left Kai devastated with no hope.
The final match begins, with Kamui against Tetsu.
Although Kamui tries his hardest, Tetsu is victorious, putting Team AL4 up one game to none.
Misaki draws upon her memory power as she battles Asaka in this second-round revenge match.
Having ordered the positions of her last 16 cards thanks to the abiltys of her cards, Misaki defeats Asaka.
The final battle between Ren and Aichi begins, with Ren initially using his PSYQualia to overpower Aichi.
Ren taunts Aichi throughout their battle, trying to get him to use his PSY Qualia. Feeling angry, Aichi does and summons Blaster Dark to the surprise of everyone. However, this causes him to change his personality back into what he was before when he first uses PSY Qualia. Meanwhile, a mysterious entity possesses Rekka temporarily, informing Kourin and Suiko of an impending doom about to happen on the planet Cray and a war between the many clans which will be decided based on the outcome of Aichi and Ren's battle. The mysterious being also explains the truth of PSY Qualia. Back to the match, Kai reminds Aichi that this was not his true self which causes Aichi to overcome his dark self. As he is confused over his two selves, Ren declares 'Final Turn' and crossride Phantom Blaster Overlord and utilizing its Persona Blast.
After calling out 'Final Turn', Ren fails to defeat Aichi as Aichi miraculously draws a Heal Trigger. Aichi then realizes his true self as he summons Majesty Lord Blaster to get Ren out of his PSY Qualia addiction. Majesty Lord Blaster's skill shocked Ren as Majesty Lord Blaster could get an extra 10000 points and an extra critical by adding both Blaster Blade and Blaster Dark in the Soul. In the end, a good ending started with Phantom Blaster Overlord defeated.
A few weeks have passed since Team Q4 won the national tournament. One day, Aichi goes to Card Capital and meets a young boy who wants Aichi to teach him how to play Vanguard. Aichi agrees and teaches the boy about Vanguard through playing a game, much like how Kai taught him. The boy, using a Gold Paladin deck, eventually drops the newbie facade. When he rides Great Silver Wolf, Garmore, he draws Aichi into a vision of the Royal Paladin's Blaster Blade, Shadow Paladin's Blaster Dark, and Kagero's Dragonic Overlord being captured by a mysterious force on the planet Cray. He then tells Aichi that a new power that can go past the boundaries must be attained in order to combat this force. After the vision, the boy disappears and Aichi discovers that his Royal Paladin deck has changed to a Gold Paladin deck. What's more is that everyone else's memories have been rewritten to think that Aichi has always used Gold Paladins, not even noticing the change.
Depressed about losing his Royal Paladin deck, Aichi meets Kai. He learns that not only has Kai's deck been changed to a Narukami deck, but also that Kai has no memory of using a Kagero deck or of Aichi using Royal Paladins. To find some answers, the two have a cardfight. As Aichi struggles to get comfortable with his new Gold Paladin deck, Kai slowly realizes that something is off. Getting his memory back, Kai nonetheless chooses to continue using his current deck, but Aichi is conflicted about using his. Kai tells Aichi that he is bound by his own limits by not wanting to use Gold Paladins and that he needs to break through them. To prove his point, Kai rides Dragonic Kaiser Vermillion, declares "Final Turn", and performs Limit Break, an ability that activates when a player has 4 or more damage. With Vermillion's Limit Break, Kai attacks all of Aichi's front-row units in one strike and wins as a result.
After receiving the invitation to the VF Circuit, Aichi wants to enter with all of the original members of Team Q4 (minus Kai). He convinces Misaki to rejoin with no problem, but then Aichi learns that Kamui has joined Team Handsome. So, he goes to Card Shop Handsome to recruit him back. When Aichi tells him about the invitation, Kamui becomes torn between his own feelings of wanting to participate in the Circuit and his promise to Team Handsome to go with them to the upcoming national tournament. It is ultimately decided to settle things with a cardfight between Aichi and Kamui. If Aichi wins, then Kamui will return to Q4 and enter the VF Circuit. If Kamui wins, then he stays with Handsome. And so, Aichi and Kamui's cardfight ensues. As Aichi tries to get used to his Gold Paladin deck, Kamui puts on the pressure with his slightly-improved Nova Grappler deck, driving Aichi to 5 damage.
With Team Q4 reunited, Aichi, Kamui, and Misaki go shopping in preparation for the VF Circuit. After they finish their shopping, they visit Card Shop PSY so that Aichi can talk to Suiko about the mystery behind the replacement of his Royal Paladin deck. Once there, they find out that the Ultra Rare girls will also be going overseas. Noticing the large amount of shopping bags that Team Q4 has, Rekka questions the team's motive for participating in the VF Circuit. When Misaki says that she's going because she was asked to, Rekka insults her for treating their ticket to the VF Circuit as a free vacation and having no intention to win. To prove her wrong, Misaki challenges Rekka to a cardfight. While using the new Angel Feather clan to use cards in her damage zone to her advantage, Rekka criticizes Misaki's deck for being good but still lacking. Rekka then shows Misaki what that missing attribute is when she rides Circular Saw, Kiriel and utilizes its Limit Break to defeat her.
Q4 arrives in Singapore. While sight-seeing, they run into their friendly rivals, Team Caesar. Kenji and his friends take them to a local university, SIT (Singapore Institute of Technical Studies), where students learn about specific studies in Vanguard and where Kenji hopes to attend when he graduates from high school. They then meet three young boys, Christopher Lo, Ali Pajeel, and Lee Shenlon, who are students of the university despite being the same age as Kamui. The SIT boys get into a heated discussion about how they got an early start in attending SIT and how there's little to no hope for those who attend later than they have. After leaving the university, Aichi sees Takuto and follows him trying to get an answer. Kourin arrives and lets him know the only way to meet with Takuto is to win the VF Circuit. Before leaving, Kourin gives Aichi a card, Incandescent Lion, Blond Ezel.
Kamui has won his match, so now it's up to either Aichi, Misaki or both to best their ninja opponents, who are much more worldly than Team Q4.
Team Q4 battles Team Divination in the 2nd round. All 3 members supposedly have psychic powers that allow them to see the future, and they each play with Oracle Think Tank decks, the same deck Misaki uses. The familiarity with the deck gives Team Q4 the advantage as they sweep Team Divination while exposing them as phony prophets. After the battle, Team Q4 runs into Team SIT Genius on the street. Kamui vows never to lose to fighters the same age as he is, and Misaki wonders how she can avoid facing off against an opponent with the power of Limit Break.
Team Q4's 3rd round match begins; their opponents are revealed to be against Chris, Ali, and Lee - Team SIT Genius. Lee Shenlon is shown having great pride, and he declares he is the only one who can defeat Chris. Meanwhile, Ali promises to defeat Kamui and steal Emi from his heart forever. Ali seems to have the advantage as Kamui is given a quick 5 damage to Ali's 3. Misaki gives Lee 3 damage and then attacks the rearguard, fearing Lee might have the power of Limit Break. That move is made void though as Lee plays a card that will give him one additional damage for a full turn, thus giving him the power to gain Limit Break.
Kamui vs. Ali and Misaki vs. Lee Shenlon finish their matches. The results will be a 1-1 draw. As the scene shifts to Aichi vs. Chris, Takuto Tatsunagi calls out to both of them with his spirit on Cray. Aichi's Psyqualia is returned, but Chris also gains the power of Psyqualia and slowly begins to go mad. Takuto states this is the only time he can interfere in a match, and in order for Aichi to gain any additional knowledge about Cray and the Royal Paladins, he will have to win the tournament.
The battle between Aichi and Chris continues, but this time both amp it up by using Psyqualia. Chris declares he will defeat Aichi with a triple slash from his School Hunter, Leo-pald, but the experience against Ren's Psyqualia could give Aichi the advantage in this match.
Q4 returns home to rest and recover for the next leg of the Circuit. Aichi learns that Kai hasn't appeared at Card Capital and hasn't been seen in the city since they left. As Aichi wonders about his missing friend, the scene shifts and reveals Kai is traveling the world getting stronger. Currently, he is in a snowy mountain region where he battles a rumored abominable snowman. It is soon revealed that the snowman is actually Kyou Yahagi in disguise, still aiming to get his revenge on Kai. Kyou has gained new cards, one of them being Demonic Lord, Dudley Emperor which has the power to Limit Break.
While Team Q4 trains at Card Shop Handsome to get ready for the next round of the VF Circuit, the group is informed that Tetsu has arrived to Card Capital, assuming that he is causing trouble. However, their assumptions are disproven when they return and see Tetsu helping out Emi and the other kids at the shop. Kamui asks Tetsu what his real intention for coming is, to which Tetsu answers by telling Q4 how weak the team is due to losing at the VF Circuit's Singapore Stage. Enraged, Kamui challenges Tetsu to prove him wrong. Tetsu accepts the challenge, and the two start their cardfight. With support from the latest expansion set, Tetsu uses new Dark Irregulars to soulcharge, and then he utilizes the Limit Break of Dark Lord of Abyss to overwhelm and defeat Kamui once again. Tetsu leaves, warning Q4 of stronger teams awaiting them in the VF Circuit.
The Seoul Stage of the VF Circuit begins with Team Q4 coming across Team Movie Stars, the local favorite favored to win the Seoul Stage. The teams head into the cardfight area where they learn special rules will be applied in this stage. Team Q4 faces off with Team Seven Seas, who are all pirates who use Granblue decks like Team Handsome. Aichi's special rule is to have a drive check for rear-guards, Misaki's rule is all turns must be completed within 30 seconds, and Kamui's rule is you can't see what you attack. Aichi trails 4 damage to 2 when he summons Incandescent Lion, Blond Ezel and places 2 grade 3 units in the rear-guard zone. This means he gets a minimum of 6 drive checks. His opponent guards twice, but thanks to 2 stand triggers, Aichi manages to pile up the damage and wins 6-4. Misaki memorizes her opponent's hand and makes it where he can't guard with a timely bind allowing her to win 6-2.
Team Q4 confronts Kai to learn why he joined the VF Circuit, and the match between Team Q4 and Team New AL4 begins. Ren battles Aichi, Kamui must try to defeat Kai, whom he has never defeated before, and the tiebreaker between Asaka and Misaki all begin. The special rule is each player starts with 2 damage and they play until 8 damage has been made, meaning that a player can activate Counterblast skills immediately and use Limit Break more quickly. Kai overwhelms Kamui with 2 Limit Breaks from Dragonic Kaiser Vermillion and defeats him 8-6. Misaki holds a slim lead on Asaka 6-5. Ren and Aichi are contacted by Takuto who gives back to Ren the power of Psyqualia and asks them what they see to lead them to victory.
The matches between Misaki vs. Asaka and Aichi vs. Ren continue. Asaka rides a new card, Silver Thorn Dragon Tamer, Luquier, and uses its Limit Break to superior call 3 units from her soul. She launches powerful attacks that Misaki cannot guard against and ultimately wins. Asaka walks away victorious while being disappointed in Misaki's performance. Meanwhile, Ren rides Spectral Duke Dragon and later attacks Aichi's Blond Ezel with it. Aichi guards against it, but then Ren utilizes the Limit Break of Spectral Duke Dragon to have it stand up and attack again. Aichi is unable to block this attack, giving Ren the victory, just as he predicted with Psyqualia. This 3-0 sweep means that Team New AL4 moves on to the next round, with Team Q4 learning how much Team New AL4 has changed.
Team Q4 watches the final round of the Seoul Stage, which pits Team New AL4 against Team Caesar. The special rule for all of the fights in this round is that only 3 rear-guard units are allowed to stand at the beginning of each turn, thus limiting overall attacking power. The matchups are Kai vs. Gai, Asaka vs. Yuri, and Ren vs. Kenji, with Ren deciding to borrow Tetsu's Dark Irregulars deck for his match. Ren and Kenji exhibit world-class play as Ren builds up his soul to power up both his vanguard Blade Wing Reijy and rear-guard units. Ren tries to attack Kenji's rear-guards to hinder his upcoming strategy, but Kenji successfully protects them. Kenji then declares "Final Turn", moves his Dimensional Robo rear-guards to the soul, and superior crossrides his new key card, Ultimate Dimensional Robo, Great Daiyusha.
After returning home from Seoul, Team Q4 runs some errands to help Aichi relax after the team's loss. Then, in front of Card Shop PSY, they meet a young blonde-haired and mysterious man named Leon Souryu, who is able to feel the "wind". The Ultra Rare trio returns, and they discover that their supposedly-closed shop is unlocked. The entire group enters, and they are surprised to find that the legendary cardfighter Daigo is there. It was believed that Daigo had gone missing for months, to which Daigo explains in a private conversation with Ultra Rare that he had been randomly teleporting from place to place. Suiko believes it is because of Daigo's deck, which is composed of Royal Paladins, one of the clans that were removed from the world, and therefore considered legendary by everyone except Aichi. Afterwards, Daigo offers up a challenge to anyone willing to cardfight with him. Before Aichi can accept, Leon steps up to be Daigo's opponent.
Team Q4 and friends travel to a distant southern deserted island with an invitation from the VF Circuit, but when they arrive, they learn that Team New AL4 has also been invited. While Team Q4 is fixated on training to get stronger, everyone else is looking for some rest and relaxation. Later that night, after dinner, Ren gathers everyone together and gets them to agree to be in a test of courage, with some having the job of scaring people and the others being put to the test. Shenanigans ensue such as the supposedly-stoic pair of Misaki and Asaka easily getting scared to the point of fainting and Kamui failing to scare Tetsu for being paired with Emi. Aichi and Kai are teamed together to go through the course, but instead of doing so, Kai takes Aichi off on his own and gives him some words of encouragement, which are topped off by a fireworks display.
Q4 and New AL4 continue their vacation on the southern island, with each member of Q4 having their own story to tell. Kamui gets depressed when he loses to Tetsu again, and his friends Reiji and Eiji cheer him up. The three then undergo a rigorous training regimine, which gives Kamui inspiration to make a new deck revolving around the Raizer series. But once again, in spite of this new deck, Kamui is defeated by Tetsu. After getting coaxed into playing beach volleyball with Ren and Asaka, Misaki cardfights with Ren, with both of them borrowing others' decks. Ren reveals the reason as to why he fights with other people's decks is to not only try and find a more suitable clan for him to use, but to also gain a better understanding of his own deck. With that in mind, Misaki constructs a new Witch-themed Oracle Think Tank deck and defeats Ren, this time borrowing Emi's Bermuda Triangle deck. Aichi turns his focus toward developing a new deck.
Q4 returns to Japan with new strategies for winning being devised. Aichi and Kamui test them in the final round of a tournament held at Card Shop Handsome. Unbeknownst to them, Kenji Mitsusada arrives, looking for Aichi. Gouki tells him that Aichi is currently in a cardfight with Kamui. Feeling anxious and being short on time, Kenji decides to leave until Gouki challenges him. It's the first-ever match between the two. Although Gouki gets a bad starting hand with no grade 2 or 3 units, he manages to smoothly superior ride with cards he sent to the drop zone, including his new ace card, Ice Prison Necromancer, Cocytus. Kenji is impressed by Gouki's determination to overcome the odds stacked against him, to which Gouki expresses his disappointment in Kenji the "Emperor" for saying such a thing to begin with. Remembering the feeling of never giving up, Kenji continues to play at his best, crossriding Ultimate Dimensional Robo, Great Daiyusha and winning the match.
Team Q4 and friends head to the Hong Kong Stage of the VF Circuit, hoping to advance to meet with Takuto. While in front of the stadium, before the fights start, they have a short run-in with three males, one big, one normal-sized, and one small. Shin vaguely remembers seeing them before, and it is then that two identical girls appear. They tell him off by saying how that group is actually a powerful team before taking their leave. The Hong Kong Stage officially begins. The unique attribute of this stage is that each cardfight will be 2-on-2 tag-battle style; the first team to deal 9 points of damage instead of the usual 6 to the opposing team is the victor. However, Kamui cannot comprehend the numerous difficult rules, leaving Aichi and Misaki to pair up and take on Team Lao (the group of three men who they met earlier) in the first round.
The tag fight between Q4's Aichi and Misaki versus Lao's Terence and Felix continues. After Misaki's attack on Felix, he strikes back with Tyrant, Deathrex to put Team Lao in the lead. Then, wanting to make up for Misaki, Aichi rides a new ace card, White Hare in the Moon's Shadow, Pellinore. With its Limit Break, getting two drive triggers, and multiple superior calls from his deck, Aichi tries to finish the game with powered-up attacks. However, Terence manages to survive with support from Felix's tag guard. On Terence's turn, he also activates Limit Break, retiring his own units to increase the attack power of Military Dragon, Raptor Colonel while also superior calling more units from his deck. Aichi defends with all of the cards in his hand, and Misaki uses the extra cards drawn from her previous turn to tag guard with him. She anticipates Terence getting a drive trigger, which he does but her tag guards nonetheless successfully block his attacks.
Q4 makes it to the semifinals of the Hong Kong Stage with Aichi and Misaki doing all of the cardfighting. After diligently studying the tag fight rules, Kamui offers to participate in the next fight. So, it is decided that Kamui and Misaki will pair up for their fight against Team Battle Weeds, a group of three kids who greatly admire the tenacity of weeds. True to their namesake, the members of Battle Weeds use Neo Nectar decks. Withstanding the Limit Break of Battle Weeds' ace card, White Lily Musketeer, Cecilia, Kamui proceeds to ride his new key card, Perfect Raizer. Its skill increases its power to exponential heights, and managing to pull a critical trigger, Kamui wins the match for Q4, thus advancing the team to the finals. However, Q4's next opponent is Team Dreadnought, with its members consisting of the two previously-encountered twin sisters, Jillian and Sharlene, and their leader, Leon Souryu.
Q4's Aichi and Kamui face off against Leon and Sharlene of Dreadnought in the finals of the Hong Kong Stage. Remembering Leon's fight with Daigo, Aichi and Kamui do their best to minimize the damage taken from Dreadnought's multi-attacking Aqua Force units. Although Aichi deals damage to Leon, he is unaffected by his attacks. Then, Aichi asks Leon what he means whenever he refers to the "wind". It is then revealed that Leon's "wind" is actually the power of Psyqualia. In a Psyqualia-induced vision, Leon tells Aichi a tale from long ago about a conflict between the many clans on the planet Cray. This war was eventually resolved by the appearance of the dominating Aqua Force armada. In the human world, the Souryu family had control over the Aqua Force which was used to hold power over the seven seas. However, for unknown reasons, the Aqua Force clan disappeared, and so did the Souryu family's power.
Aichi uses Psyqualia to gain a winning image. Although things seem to go just as he envisioned, his attacks are foiled by Leon's perfect defense and Sharlene's tag guard. On the next turn, Sharlene again uses the Limit Break of Navalgazer Dragon and forces both Kamui and Aichi to use a lot of their cards to defend against its attack. Then, Kamui says that his turn will be the last as he rides another Perfect Raizer, bringing its power up to full potential. However, the usually-mellow Sharlene easily blocks Kamui's attacks and grows angry with his indirect "Final Turn" declaration. On Leon's turn, he follows his "wind" and calls another Blue Storm Dragon, Maelstrom as a rear-guard, now having two Maelstroms as Aichi had seen through Psyqualia. Leon attacks him with his vanguard Maelstrom powered up via its Limit Break, and Kamui tries to tag guard for Aichi.
Aichi is feeling desperate by the fact that he and Q4 must win the Japan Stage of the VF Circuit. To better prepare the team, Shin recommends for Aichi, Kamui, and Misaki to battle against other stronger, non-Q4-affiliated cardfighters. Aichi takes a look at his Blond Ezel card and is reminded about Kourin, the person who gave it to him. So, Q4 goes to Card Shop PSY and requests for the Ultra Rare girls to cardfight with them for training purposes. They accept, and thus the battles ensue. The first match-up is between Aichi and Kourin, who now uses an Angel Feather deck. Aichi gains the upper hand when he superior rides Pellinore, but Kourin uses her Angel Feathers' skills to swap cards from her damage zone and then calling them. As the fight continues, Kourin antagonistically puts down Aichi by telling him to give up and how he's reached his limits. He proves her wrong and shows his determination when he rides Blond Ezel and activates its Limit Break to defeat her.
Kamui and Suiko's cardfight continues. Suiko uses Shamsiel's Limit Break and the Angel Feather stategy of switching cards from her hand with ones from the damage zone, thereby increasing her units' attack strength and acquiring the cards she wants. She also tells Kamui that power alone is not enough to win. Despite her words, Kamui manages to win through the sheer force of Perfect Raizer. Then, the rematch between Misaki and Rekka begins. Although Misaki gets the first turn, Rekka gets a grade 3 in play first by superior riding her new ace card, Crimson Impact, Metatron. With its Limit Break, Rekka superior calls more Angel Feathers from her damage zone and pressures Misaki to use a lot of her cards to block against her attacks. The two then have a conversation about how it was Rekka who motivated Misaki to change her deck. Misaki further elaborates that she was hesitant on changing her deck because she thought it would also mean changing the memories associated with her first deck.
The Japan Stage of the VF Circuit is drawing near, and many teams, including the victors of the previous stages, will appear there. As Team Dreadnought's plane lands in Japan, it is directed to and locked in a hangar with a jungle environment inside. It is really a trap set by Kyou Yahagi and his Team Avengers (all dressed as bugs), who plan to take Dreadnought's spot in the VF Circuit. Although Jillian and Sharlene handily take care of Kyou's teammates, he nonetheless challenges Leon to a cardfight. Now using a Megacolony deck after witnessing the strength of insects from his experience in the jungle, Kyou prevents some of Leon's units from standing and retires others. Thus, he seals the Aqua Force strategy of launching multiple attacks and Blue Storm Dragon, Maelstrom's Limit Break.
It's time for the last leg of the VF Circuit, the Japan Stage. Taking place in an amusement park, many familiar teams have gathered. The aspect for this stage is that each team member will individually fight others in three separate stadiums. Each victory that a cardfighter gets will earn his/her team 1 point; the team with the most points by the end is the winner of the entire Japan Stage and will go on to face the previous stages' winners at the Final Stage. What's more is that "special reserve" cardfighters like Team Unknown (composed of the masked trio of King Z, Queen Y, and Joker X) will participate and act as obstacles for all of the teams. With the rules fully explained, Aichi and Q4 resolve themselves to win the Japan Stage. And so, the fights begin. Misaki and Kamui win their respective matches. On the other hand, Aichi is in a close fight in a rematch with Team Jurassic Army's Gunji Ryudo.
After Nagisa appears in a horse-ridden carriage led by Team Handsome, she greatly exaggerates about being married to Kamui, which causes the audience to misunderstand the situation and embarrasses him in the process. Nonetheless, the two kids begin their cardfight, which is being treated as a wedding ceremony by Team Handsome. Nagisa's Death Army units battle Kamui's Beast Deity units in this Nova Grappler mirror match (with the latter forced to wear a groom's tuxedo). After protecting himself from the Limit Break of Nagisa's new ace, Infinite Corrosion Form, Death Army Cosmo Lord, Kamui crossrides his new key card which he received after Q4's time at Card Shop PSY: Ultra Beast Deity, Illuminal Dragon. With multi-pronged attacks, Kamui defeats Nagisa, who decides to leave him alone (for now, at least). Elsewhere, Aichi and Misaki win more matches for Q4. Shortly after, Q4's next opponent, Team Unknown, approaches each member. It will be Aichi vs. King Z, Misaki vs.
It's Team Q4 against Team Unknown in the last round of the Japan Stage. Aichi's opponent, King Z, is revealed to be Jun Mutsuki, the King of Underground Fights, although Aichi does not immediately recognize him. Meanwhile, Misaki battles Queen Y and sees through her disguise. Queen Y is actually Yuri Usui from the defunct Team Caesar, and Yuri now uses the deck she originally had before joining Caesar: Oracle Think Tank. As for Kamui, he has not realized who Joker X is. As they battle, Joker X's voice and style of play with Dark Irregulars slowly remind Kamui of a certain someone. Aichi and Jun conduct their cardfight. Jun's "dark hero" Dimension Police units decrease the power of Aichi's vanguard. Because of this, he is forced to either take damage or use a lot of shields to guard. Even though Aichi loses Blond Ezel, he remembers his reasons for fighting and stays resolved. Using Psyqualia to gain an image of victory, Aichi superior rides Pellinore for a comeback.
Yuri's Battle Sisters deal major damage to Misaki, giving her the lead 1-5. Misaki strikes back by riding her new ace card, Goddess of the Sun, Amaterasu. Yuri tries to guard her attack, putting Misaki in the same situation as the last time they fought each other. Misaki decides to take a chance, which pays off when she drive checks a critical and heal trigger, and evens out the damage 4-4. Thanks to Amaterasu and its Limit Break, Misaki ultimately wins. Meanwhile, Kamui continues his battle with Joker X, who rides No Life King, Death Anchor. Kamui defends himself against its terrifying skill with a lot of his cards. On the following turn, Kamui crossrides Illuminal Dragon and activates its Limit Break to stand his remaining units, thus forcing X to not guard against his attack. Kamui defeats Joker X without ever learning his true identity. Winning every match they had, Q4 is crowned the victor of the Japan Stage.
As Team Dreadnought stops everyone from moving forward, Leon reveals that his true purpose for entering the VF Circuit was to thwart Takuto's plan of freeing Cray from the enigmatic enemy. Leon also says he was the one who let the Royal Paladin, Shadow Paladin, and Kagero clans be sealed away by the enemy. His reasons for doing so are to set the Aqua Force clan free (which was also captured by the same foe), restore the Souryu family to its former glory, and then rule the world. Leon's Psyqualia is amplified by the dark powers of the enemy and blows everyone away. Later, after being knocked unconscious, Q4 awakens and speaks with an injured Takuto, who gives more revelations. He discloses the name of the mysterious enemy: Void, an evil power of emptiness that is currently encompassing the majority of Cray and will make its way to Earth if not stopped.
Aichi once again battles Chris, who uses Psyqualia to foresee his victory. Similar to their last match, Chris predicts that he will win when his new ace card Battler of the Twin Brush, Polaris strikes Aichi's Blond Ezel three times in one turn. While Chris' Psyqualia prophecies initially seem to be going the way he said they would, Aichi knows that Psyqualia is not 100% accurate nor is it just a dark power. On the turn Chris declares his victory, Aichi blocks the last two attacks from Polaris, therefore throwing off his winning Psyqualia image. Then, Aichi crossrides his new key card gained from his experience at Card Shop PSY: Blazing Lion, Platina Ezel. With its Ultimate Break, Aichi increases the power of all his rear-guards, thus overwhelming and defeating Chris. Now knowing what Psyqualia really is, Chris learns the error of his ways and is forgiven by his friends Lee and Ali.
While Jillian and Sharlene take on Ren and Asaka in a tag fight, Kai begins his battle with Leon. As the two fighters clash, Leon reveals his past. As it turns out, the legend of a child who would call forth the "wind" and lead the second coming for both the Souryu family and Aqua Force clan was just a fairy tale made up by the Souryu chief only meant to provide (false) hope to the young Leon, Jillian, and Sharlene. Eventually, the Souryu and Aqua Force would be forgotten and die out. Desperate to find power to save both, Leon met Void, who offered him Psyqualia. He accepted the power, and thus Leon became that prophesied Souryu child, turning that fairy tale into a reality. Back to the cardfight, Kai, who is furious at Leon's selfish actions of betraying the 3 clans, rides Dragonic Kaiser Vermillion and announces that he will defeat him.
Kai and Leon continue their cardfight with each side using their respective vanguards' Limit Break abilities. After he insults Leon by calling him a pawn to Void, Kai crossrides his new trump card: Dragonic Kaiser Vermillion "THE BLOOD". He activates its Ultimate Break to give it extra critical value and power, forcing Leon to use his few remaining cards to defend. Kai manages to deal 2 more points of damage, presumably ensuring his victory, but Leon gets a heal trigger to stay in the game. On the following turn, Leon also crossrides his new ace card: Blue Storm Supreme Dragon, Glory Maelstrom. Its Ultimate Break also makes Kai use the last of his cards to hopefully block its attack. However, Leon drive checks a critical trigger, thus plowing through Kai's guardians and winning the match. After Glory Maelstrom's attack, the dust settles and reveals Leon standing over the fallen Kai. Just arriving to the scene, Aichi runs towards Kai and picks him up.
The final battle between Aichi and Leon begins, with the latter predicting via Psyqualia that he will win when his Glory Maelstrom attacks Aichi's Blond Ezel. Signs show of the nothingness that is Void slowly destroying the dimension and creeping its way to Aichi. The darkness eventually affects Aichi as he falls unconscious and loses the will to fight. However, he remembers his loved ones and then hears a familiar voice, both of which help Aichi to stand up and continue the battle. He activates the Limit Break of Blond Ezel to superior call an astral form of his original avatar card: Blaster Blade Spirit. But even with that, Leon withstands Aichi's attacks and then crossrides Glory Maelstrom...
The fight between Aichi and Leon reaches its climax. After Leon uses the Ultimate Break of Glory Maelstrom to increase its power and prevent Aichi from guarding with grade 1 or higher units, Aichi attempts to guard with two grade 0 units. However, Leon drive checks a heal trigger, which gives Glory Maelstrom enough power to penetrate Aichi's defense. Aichi survives the attack thanks to his own heal trigger. Leon slowly grows weakened after absorbing Void's power as Aichi crossrides Platina Ezel and activates its Ultimate Break to overpower and finally defeat Leon. Void leaves Leon's body, and Takuto opens the path to the planet Cray, declaring that Aichi's Gold Paladin clan is the rightful leader of Cray. Aichi holds up his deck, and with a reformed Leon's help, the Gold Paladins and Aqua Force units dispel Void's darkness from Cray and free the sealed Royal Paladin, Shadow Paladin, and Kagero clans.
Months after the conclusion of the VF Circuit, Aichi enters high school as a freshman at Miyaji Academy. However, he has trouble adjusting to his new school life due to the academy's heavy emphasis on studies. After school, Aichi goes to Card Capital while being tailed by a classmate, Naoki Ishida. There, he sees the many customers playing Vanguard, which Naoki has no knowledge about. He spots Aichi conversing with Team SIT Genius in the back of the shop. Curious by how different Aichi's behavior is in the card shop compared to how he acts at school because of a card game, Naoki becomes intrigued to Vanguard. And so, Aichi teaches Naoki about Vanguard through playing an actual match, with the latter being lent a new Narukami trial deck to use from Shin. As they cardfight, Naoki slowly gets immersed into the game. After Aichi eventually wins, Naoki buys the trial deck and hastily leaves in a frustrated manner, which worries Aichi.
The news of Kourin transferring into Aichi's class becomes a hot topic, especially when the male classmates start talking to Aichi to get closer to her once they learn that the two know each other. Then, Aichi gets an idea on how to promote Vanguard at his school. Because there is no Cardfight Club, Aichi decides to make one himself. The next day, he tries to recruit enough members to officially start the club (needing a minimum of five people, including himself) by handing out leaflets in front of the school. His pleas fall on deaf ears until Kourin agrees to be a member. Her enlistment is followed by several other boys who want to join (only to be with Kourin), but she proposes that anybody who wants to become club members will have to defeat either her and Aichi in cardfights before they can enter. The two easily beat all of the challengers, but then Naoki steps up to play against Kourin with honest feelings of wanting to join the club.
Aichi's Cardfight Club is attracting attention all around the school as male classmates (who are mostly interested in being with Kourin) have him teach them the rules of Vanguard and again attempt to play against Kourin in order to be inducted to the club but to no avail. Additionally, the female students gossip about a rumor that claims Aichi only started the club to get close to Kourin, which makes Misaki worry. Aichi tries to ask Misaki to join the club, but she declines because of her job at Card Capital. Kourin gets an unsettling feeling that there is someone watching her, with Naoki suspecting that it could be a stalker. Naoki eventually confronts the stalker who turns out to be a classmate, Shingo Komoi. Naoki threatens to beat him up, but Shingo suggests to settle things with a cardfight instead. Despite modifying his Narukami deck, Naoki's inexperience at Vanguard causes him to struggle against Shingo's Murakumo deck.
The student council president of the Miyaji Academy High School Division deems Aichi's Cardfight Club to be unnecessary for the school and orders the vice president, Suwabe, to devise on how to abolish it. Elsewhere, the Cardfight Club finds an empty classroom to serve its official headquarters. Then, the school's American football team, the Miyaji Vipers, barges in and takes the club outside to the academy's sub-ground where the Vipers' quarterback/captain, Ikki "the Catapult" Kongou, challenges Aichi to a cardfight, with the former appropriately using a Spike Brothers deck. This is an elaborate plan set up by Suwabe to have Ikki defeat Aichi and thereby crush the Cardfight Club members' spirits into not wanting to continue the club. Ikki uses strong Limit Break effects of the latest Spike Brothers to push for victory, but Aichi successfully defends and makes it to his next turn.
After Aichi tells his friends at Card Capital about how his school's student council is causing problems for the Cardfight Club, he repeatedly requests for Misaki to join as the fifth member. However, she still turns him down, having mixed feelings on the matter and being insulted by Kourin for not being serious on becoming a member. Then, to quickly shut down of the Cardfight Club, the student council creates a deadline for all potential clubs with at least five members to report to the council, or else they will not be officially recognized by the school. At the last second, Misaki declares herself as the Cardfight Club's fifth member after resolving her feelings of earnestly wanting to join the club. As an initiation test and to prove herself to Kourin, Misaki cardfights Aichi.
Miyaji Academy's unofficial Cardfight Club is set up to have an intramural match against Hitsue High School's Vanguard Club, in which Kai, Miwa, Morikawa, and Izaki are members. The two teams play in a best-of-5 match, and opponents are randomly selected. Under the conditions that the Miyaji Academy student council president created, if the Cardfight Club loses this match, then it will be dissolved. In the first game, Naoki fights Kai, with both using Eradicator-themed Narukami decks. Naoki combines both the Break Ride of Eradicator, Vowing Sword Dragon and the Limit Break of Eradicator, Gauntlet Buster Dragon to retire Kai's units and gain more critical value and power, but Kai manages to survive the assault. Then, Kai uses a similar devastating combo with Vowing Sword and Eradicator, Dragonic Descendant. Although Naoki blocks his first attempt, Kai activates Descendant's Limit Break to have it stand up, gain another critical, and attack again.
Kourin defeats Izaki, which ties the score 1-1. The third game pits Misaki against Hitsue Vanguard Club's ringer and old Q4 teammate, Kamui Katsuragi. Although Kamui gets an early lead, Misaki mounts a comeback with Battle Deity of the Night, Artemis. Kamui then combines the Break Ride of Beast Deity, Ethics Buster and the Limit Break of Ultra Beast Deity, Illuminal Dragon to stand four of his rear-guards to launch multiple attacks in one turn. However, Misaki protects herself, only taking one point of damage from Kamui's five attacks. In what seems to be a hopeless situation, Misaki rides Eternal Goddess, Iwanagahime and uses its Limit Break to retire Kamui's front-row units. Weakening Kamui's defenses, Misaki wins and puts Miyaji Academy up 2-1. In the fourth game, Shingo is selected to fight against Miwa. Before the fight, Shingo underestimates Miwa, which ends up being his undoing when Miwa demolishes him and evens the score 2-2. So, it's Aichi vs.
Aichi faces Morikawa in the last fight of this intramural match. Although initially mad with using Kai's Kagero deck and not his own, Morikawa nonetheless puts a great amount of pressure on Aichi. All the while, Kai watches the fight as an opportunity to see if his Kagero deck is strong enough against the current Aichi, who strikes back with the Break Ride of Solitary Liberator, Gancelot to empower itself and his rear-guards. Morikawa defends and makes it to his next turn, in which he rides Dragonic Overlord the End. Pairing its Personablast with the Break Ride effect of Dauntless Drive Dragon, Morikawa attacks Aichi with the End three times in a row. Determined to win for the sake of the Cardfight Club, Aichi withstands the onslaught and then uses Gancelot's Break Ride again on the following turn to land a final blow. Aichi emerges victorious over Morikawa, meaning that the Miyaji Academy Cardfight Club wins the intramural match.
Now that the Cardfight Club has become official, the new faculty advisor Nakamurabashi makes the club decide on a captain and vice-captain for the club by order of the student council president. Since Aichi was the person who started the club, he reluctantly accepts the position of captain. As for who should be the vice-captain, Shingo is the only person who honestly wants the job while the others are apathetic on the matter. Not wanting to make a hasty decision, Nakamurabashi recommends to hold off until tomorrow on who to elect for vice-captain. After school, Misaki is convinced by her friend Akari to try out for vice-captain. The same happens with Kourin being persuaded by Takuto. The club meets the next day, and when Nakamurabashi asks again for who wants to be the vice-captain, Shingo, Naoki, Misaki, and Kourin all raise their hands. To finally settle things, the four cardfight each other with the overall winner becoming the vice-captain.
Shingo tells Naoki about a Cardfight Circle formed in the middle school division of Miyaji Academy. Shingo suggests that the two of them should pay a visit to the circle and build a relationship b